Vol. 10, Issue 6 (2021)

Author(s):
Harshitha HM, Chandrashekar SY, Harishkumar K and Pradeep Kumar CM

Abstract:
Horticulture plays a key role in increasing the agricultural GDP by its high valued crops. Floriculture is one such allied sector of Horticulture which involves high valued, export oriented commercial flower crops and ornamental plants, playing as a major contributing sector to Horticulture. Due to uprising urbanization of the society worldwide, especially in India, demand for flower and ornamental crops is increasing. In order to fulfill the raising demands year-round and off-season production of these crops is necessary. So, exploitation of new techniques is needed to increase the production and productivity. Photoperiod manipulation is one of the effective techniques to produce offseason flowers and to do flower forcing in case of photosensitive crops like long day plants and short-day plants. Photoperiodism is a physiological process, which is correlated with the day length of the particular season and responsible for the developmental activities in the plants. Photoperiodic flowering in plants is regulated by photoreceptors including the red/far-red light-receptor phytochromes and the blue light-receptor cryptochromes, which can be altered by artificial lighting and shading by using different light sources and blackout cloths, respectively. Photoperiod regulation is also used intensively in potted ornamental plants like poinsettia, petunia etc. to reduce the plant height and shape of the plants to maintain the consumer appeal. Date of harvesting or flowering can be effectively scheduled by exploiting the daylength. In this paper reviews on photoperiod regulation techniques, different light sources and phytochrome manipulation are discussed.